164 KED ROT Ol' SUGAKCANE. 



bud is less readily infected, luoculutions made by placing on the 

 bud scales, in a moist atmospliere, fresh acervuli with spores, from 

 a pure culture, showed little progress at the end of a month. 

 There was a slight reddening of the scale, especially along the 

 margin and hyphse were numerous in the reddened part. The 

 underlying bud layers w^ere only faintly discoloured and very few 

 h}'ph8B had entered them. The deeper layers of the bud were cjuite 

 free. The buds were swelling at the time of inoculation and the 

 progress of the infection was so extremely slow that it is doubtful 

 if the young shoot could be reached before the outer layers had 

 withered or lost contact with it. This is in harmony with our 

 general experience that uninjured young shoots are not found 

 attacked by red rot, unless the parent stem is also infected. 



The adventitious root eyes are much more easily infected. 

 Twelve Samsara canes were inoculated, in the same manner as in the 

 last experiment, on April ICth, 1912, the root origins being promi- 

 nent but quite sound and miinjured. On the 24th, 9 were examined 

 and were all found infected, the hyphse being well estabhshed and 

 growing in towards the pith of the main stem. The experiment 

 was repeated on May 22nd, 1913. Four perfectly healthy canes of a 

 thin variety which had a good development of young, clean, ad- 

 ventitious roots, varying from about one-eighth of an inch to one 

 inch in length, were inoculated in the laboratory in the manner 

 described above. The culture used was five days old and 16 roots 

 in all were inoculated. One root was sectioned after a w'eek and 

 found to have taken infection well. The penetration of the liypha^ 

 into the tissues was clearly visible and is shown in fig. 3. Jleddening 

 had extended down the root and penetrated about 1 1 mm. into the 

 main stem. Characteristic hyphsD of CoUetotrichum wqyq found in 

 the reddened part of the stem. Two days later 3 more roots were 

 examined, and the same conditions found. On this day the rind at 

 the base of the root w\as found slightly discoloured and the dis- 

 coloration extended during the following days, until it was clearly 

 visible externally in all the inoculations. The normal dark green 

 colour of the rind changed to a dirty mottled red, which spread 



